Yes, I believe the improvements are leasehold improvements that are part of the lease (20 years, which will likely exceed useful life) That doesn’t mean that the improved piece of the facility is being sub-leased to Advent. I would assume they will need to do their own leasehold improvements for other client capacity.
We know as a hard fact both finished clean room suites and the 2 unfinished suites are subleased to Advent. Along with the cryostorage and lab space.